116 lines
5.1 KiB
HTML
116 lines
5.1 KiB
HTML
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html>
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<!-- Copyright (C) 1988-2016 Free Software Foundation, Inc.
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Permission is granted to copy, distribute and/or modify this document
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under the terms of the GNU Free Documentation License, Version 1.3 or
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any later version published by the Free Software Foundation; with the
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Invariant Sections being "Funding Free Software", the Front-Cover
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Texts being (a) (see below), and with the Back-Cover Texts being (b)
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(see below). A copy of the license is included in the section entitled
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"GNU Free Documentation License".
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(a) The FSF's Front-Cover Text is:
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A GNU Manual
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(b) The FSF's Back-Cover Text is:
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You have freedom to copy and modify this GNU Manual, like GNU
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software. Copies published by the Free Software Foundation raise
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funds for GNU development. -->
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<!-- Created by GNU Texinfo 5.2, http://www.gnu.org/software/texinfo/ -->
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<head>
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<title>Using the GNU Compiler Collection (GCC): Java Exceptions</title>
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<meta name="description" content="Using the GNU Compiler Collection (GCC): Java Exceptions">
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<meta name="keywords" content="Using the GNU Compiler Collection (GCC): Java Exceptions">
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<meta name="resource-type" content="document">
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<meta name="distribution" content="global">
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<meta name="Generator" content="makeinfo">
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<link href="index.html#Top" rel="start" title="Top">
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<link href="Option-Index.html#Option-Index" rel="index" title="Option Index">
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<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
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<link href="C_002b_002b-Extensions.html#C_002b_002b-Extensions" rel="up" title="C++ Extensions">
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<link href="Deprecated-Features.html#Deprecated-Features" rel="next" title="Deprecated Features">
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<link href="C_002b_002b-Concepts.html#C_002b_002b-Concepts" rel="prev" title="C++ Concepts">
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<style type="text/css">
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-->
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</style>
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</head>
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<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000">
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<a name="Java-Exceptions"></a>
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<div class="header">
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<p>
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Next: <a href="Deprecated-Features.html#Deprecated-Features" accesskey="n" rel="next">Deprecated Features</a>, Previous: <a href="C_002b_002b-Concepts.html#C_002b_002b-Concepts" accesskey="p" rel="prev">C++ Concepts</a>, Up: <a href="C_002b_002b-Extensions.html#C_002b_002b-Extensions" accesskey="u" rel="up">C++ Extensions</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p>
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</div>
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<hr>
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<a name="Java-Exceptions-1"></a>
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<h3 class="section">7.12 Java Exceptions</h3>
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<p>The Java language uses a slightly different exception handling model
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from C++. Normally, GNU C++ automatically detects when you are
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writing C++ code that uses Java exceptions, and handle them
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appropriately. However, if C++ code only needs to execute destructors
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when Java exceptions are thrown through it, GCC guesses incorrectly.
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Sample problematic code is:
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</p>
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<div class="smallexample">
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<pre class="smallexample"> struct S { ~S(); };
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extern void bar(); // <span class="roman">is written in Java, and may throw exceptions</span>
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void foo()
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{
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S s;
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bar();
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}
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</pre></div>
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<p>The usual effect of an incorrect guess is a link failure, complaining of
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a missing routine called ‘<samp>__gxx_personality_v0</samp>’.
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</p>
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<p>You can inform the compiler that Java exceptions are to be used in a
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translation unit, irrespective of what it might think, by writing
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‘<samp>#pragma GCC <span class="nolinebreak">java_exceptions</span><!-- /@w --></samp>’ at the head of the file. This
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‘<samp>#pragma</samp>’ must appear before any functions that throw or catch
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exceptions, or run destructors when exceptions are thrown through them.
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</p>
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<p>You cannot mix Java and C++ exceptions in the same translation unit. It
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is believed to be safe to throw a C++ exception from one file through
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another file compiled for the Java exception model, or vice versa, but
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there may be bugs in this area.
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</p>
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</body>
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</html>
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